Dentists often administer local anesthetic to patients to minimize pain during dental procedures. Many dentists and patients, however, are dissatisfied with the results that dentists achieve using traditional anesthetic injection techniques. Problems with administration of anesthetic include: delays between injection and effect, the long duration and extent of postoperative numbness for patients, and the occasional inability to achieve total anesthesia.
One prior art solution was the intraosseous injection technique developed in the early 1900's. The intraosseous injection technique is a 3-step procedure. First, the gingiva over a target point of perforation, (the point between the problem tooth and the adjacent tooth) is topically anesthetized. Second, a dentist drills through the cortical plate of the selected tooth to create a hole. Lastly, local anesthetic solution is injected through the hole into the cancellous bone.
The intraosseous injection technique eliminated many of the problems of the traditional injection. The anesthetic took effect quickly and efficiently and caused little postoperative numbness. In addition, unlike other techniques, it worked well in almost all patients. However, the intraosseous injection technique had many problems. In addition to being difficult to perform, the technique produced large holes causing significant bone trauma with increased risks of bone infection.
One prior art improvement of the intraosseous injection technique was the development of the Stabident System which involved the use of a drill with a small diameter (27 G hypodermic needle) drill bit. The use of the small drill bit reduced tissue damage and the risk of infection.
In spite of these advantages, the Stabident System had several drawbacks. In particular, dentists were still required to switch to a hypodermic needle to inject anesthetic once a hole was drilled with the small drill bit. This injection step is difficult because the opening produced by the small drill bit is often difficult to locate because it is covered by soft gingival tissue. Another problem with the Stabident system is that the stainless steel drill bits are not properly tempered. As a result of the this the drill bits occasionally wear out prematurely. Worn out drill bits generate excessive heat during use that may cause heat damage to the surrounding bone tissue. In addition, excessive heat levels occasionally cause melt-down and detachment of the plastic hub attached to the drill bit. This can result in the detached drill head being left inside the patient's jaw bone leading to further complications.
Rotary dental tools with hollow bits have been used in the past as a grinding tool. Such a tool has a low speed and relatively large-diameter hollow bit for grinding bone while supplying water to the grinding area to lubricate and flush particles. However, this art does not disclose a means to supply anesthetic or medication to a tooth.